$\dfrac{5}{4} \div \dfrac{8}{9} = {?}$
Explanation: Dividing by a fraction is the same as multiplying by the reciprocal of the fraction. The reciprocal of $\dfrac{8}{9}$ is $\dfrac{9}{8}$ Therefore: $ \dfrac{5}{4} \div \dfrac{8}{9} = \dfrac{5}{4} \times \dfrac{9}{8} $ $ \phantom{\dfrac{5}{4} \times \dfrac{9}{8}} = \dfrac{5 \times 9}{4 \times 8} $ $ \phantom{\dfrac{5}{4} \times \dfrac{9}{8}} = \dfrac{45}{32} $